SEARCH · PubMed Health

Results for “Proliferation”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 271 records · Page 15Linked to original sources

PubMed1993

Proliferating trichilemmal cyst. Report of four cases, two with nondiploid DNA content and increased proliferation index.

Proliferating trichilemmal cyst (PTC) is an uncommon tumor that usually arises on the scalp of elderly women. Its biologic nature is that of a benign lesion with occasional local recurrences. PTC can be confused both grossly and microscopically with squamous cell carcinoma and malignant PTC. Distinction between these lesions has historically been made on a histologic basis. We present four cases of PTC. Histologically, the lesions consisted of lobules of basaloid cells admixed with larger pale-staining cells with abrupt trichilemmal type of keratinization and peripheral palisading embedded in a fibrous stroma. Flow cytometry performed on nuclear extracts of the lesions revealed two of the four lesions to have nondiploid DNA content. Proliferation index, measured by immunohistochemical staining with Ki-67 monoclonal antibody along with mitotic rate count, was higher in the two nondiploid lesions as compared with their diploid counterparts. The results raise the question of the significance of aneuploidy and increased proliferation indices in otherwise benign PTC.

Adult↗

PubMed1993

Chicken ovalbumin upstream promoter transcription factor (COUP-TF) binds to a peroxisome proliferator-responsive element and antagonizes peroxisome proliferator-mediated signaling.

Peroxisome proliferators form a family of diverse xenobiotic compounds that includes hypolipidemic agents, herbicides, and plasticizers. These compounds activate transcription of a subset of nuclear genes including those encoding peroxisomal fatty acid beta-oxidation enzymes, whose elevated activities can lead to hepatocarcinogenesis. Induction of the genes encoding fatty acyl-CoA oxidase and hydratase-dehydrogenase, the first and second enzymes of the pathway, is mediated by peroxisome proliferator-activated nuclear receptors (PPARs) that bind to upstream responsive elements (PPREs) through heterodimerization with retinoid X receptors. We demonstrate that the chicken ovalbumin upstream promoter transcription factor 1 (COUP-TF1), another member of the nuclear hormone receptor superfamily, binds to the hydratase-dehydrogenase PPRE in vitro and in vivo and antagonizes PPAR-dependent signaling. These data suggest that members of the COUP-TF family play a role in modulating receptor-mediated activation of peroxisome proliferator-responsive genes.

Animals↗

PubMed1993

Activin A suppresses proliferation of interleukin-3-responsive granulocyte-macrophage colony-forming progenitors and stimulates proliferation and differentiation of interleukin-3-responsive erythroid burst-forming progenitors in the peripheral blood.

We examined the effects of activin A on the proliferation and differentiation of immature hematopoietic progenitors prepared from peripheral blood (PB) using methylcellulose and liquid-suspension culture. In a kinetic analysis, colony formation by PB granulocyte-macrophage colony-forming unit (CFU-GM) was delayed in a dose-dependent manner by the addition of activin A only when stimulated with interleukin-3 (IL-3), but not when stimulated with granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), or stem cell factor (SCF) plus G-CSF. DNA-synthesizing CFU-GM was increased by IL-3, but this effect was abolished by activin A. In contrast, PB erythroid burst-forming unit (BFU-E) was accelerated by the addition of activin A only when exposed to IL-3 plus erythropoietin (Epo), but not when exposed to Epo or Epo plus SCF. DNA-synthesizing BFU-E was increased by IL-3 and activin A, alone and additively in combination. In a mixed culture of myeloid and erythroid progenitors, activin A increased the numbers of BFU-E and CFU-Mix colonies at concentrations of 1 and 10 ng/mL and decreased the number of CFU-GM colonies in a dose-dependent manner. However, in a liquid-suspension culture of erythroid progenitors, activin A decreased total cell count and the percentage of hemoglobin-containing cells only when cells were exposed to IL-3 plus Epo. These results indicate that activin A suppresses the proliferation of IL-3-responsive CFU-GM progenitors and stimulates the proliferation and differentiation of IL-3-responsive BFU-E progenitors, and suggest that activin A acts as a commitment factor of immature hematopoietic progenitors for erythroid differentiation.

Activins↗

PubMed1996

Differences in cell proliferation and prognostic significance of proliferating cell nuclear antigen and Ki-67 antigen immunoreactivity in in situ and invasive carcinomas of the extrahepatic biliary tract.

BACKGROUND: Cell proliferative activity is an important indicator of growth and behavior of various human tumors. Immunostaining of tissue sections with proliferating cell nuclear antigen (PCNA) and Ki-67 antibodies appears to be reliable in the assessment of tumor cell proliferation. This study examined differences in cell kinetics between neoplastic and nonneoplastic lesions of the gallbladder and biliary tract using an antibody against PCNA and Ki-67. METHODS: There were a total of 27 cancer cases comprising patients with invasive carcinoma of the gallbladder (n = 13), common bile duct (n = 5) and ampulla of Vater (n = 8). Cases of chronic cholecystitis (n = 11) from the nonneoplastic group; carcinoma in situ (CIS) of the gallbladder (n = 4) and ampulla (n = 6) from the noninvasive group. Cell cycle activity was determined in sections of routinely formalin fixed, paraffin processed, biopsy material using immunohistochemical stains for the monoclonal PCNA, PC10, KI-67, and MIB-1. The expression of PCNA and MIB-1 in these conditions was determined by calculating the percentage of cell nuclei that stained positively to obtain the PCNA and MIB-1 indices, respectively. RESULTS: The PCNA and MIB-1 indices in chronic cholecystitis were significantly lower than those obtained in both moderately and poorly differentiated adenocarcinoma of the gallbladder (P < 0.001). Similarly, cases of ampullary and gallbladder CIS had significantly lower PCNA and MIB-1 indices than the invasive carcinoma cases (P < 0.001). There was a strong correlation between PCNA and MIB-1 expression (r = 0.828, r2 = 0.686; P = 0.001), although the PCNA index was generally higher than that of MIB-1. The poorly differentiated adenocarcinomas of the gallbladder had higher mean PCNA and MIB-1 indices but reduced patient survival when compared with the moderately differentiated carcinomas. CONCLUSIONS: In conclusion, gallbladder, ampulla, and common bile duct carcinomas have significantly higher PCNA and MIB-1 indices than CIS and nonneoplastic lesions. Because tumors with higher PCNA or MIB-1 indices are associated with a poorer prognosis, both PCNA and MIB-1 may be useful markers of tumor cell proliferative activity and biologic behavior in gallbladder, ampullary, and common bile duct carcinomas.

Adenocarcinoma↗

PubMed1992

Cell proliferation in childhood acute leukemia. Comparison of Ki-67 and proliferating cell nuclear antigen immunocytochemical and DNA flow cytometric analysis.

The proliferative activity of bone marrow leukemia cells was determined by DNA flow cytometric (FCM) analysis and labeling index (LI) of Ki-67 monoclonal antibodies and proliferating cell nuclear antigen (PCNA) autoantibodies in 73 children with acute leukemia. LI of Ki-67 varied greatly from patient to patient (range, 0.4% to 42.2%; mean, 18.8%) and differed significantly between acute lymphoblastic leukemia (ALL) and acute nonlymphoblastic leukemia (ANLL). In ALL, the Ki-67 LI showed a positive correlation with the S-phase fraction (SPF) determined by DNA FCM analysis, whereas, in ANLL, there was a discrepancy between the Ki-67 LI and SPF. In contrast, LI of PCNA varied less among the patients (range, 57.2% to 100%; mean, 90.3%), and the value was always higher than that of the Ki-67 LI in individual patients. A significant relationship between PCNA LI and the percentage of blast cells was found in peripheral blood leukocytes from patients with leukemia. These results suggest that the Ki-67 LI reflects differences in the proliferative activity depending on the subtype of the disease and that the PCNA LI is useful as a marker of proliferating cells.

Blast Crisis↗

PubMed2002

Autoimmune responses to proliferating cell nuclear antigen multiprotein complexes involved in cell proliferation are strongly associated with their structure and biologic function in patients with systemic lupus erythematosus.

OBJECTIVE: To analyze the reaction of lupus sera with proliferating cell nuclear antigen (PCNA) multiprotein complexes (PCNA complexes), which are part of the protein machinery involved in cell proliferation. METHODS: PCNA complexes were purified from rabbit thymus extract by affinity chromatography using anti-PCNA monoclonal antibodies (TOB7, TO17, and TO30); monomeric and trimeric PCNA forms (AK-PCNA) were purified using anti-PCNA serum AK. The reactions to these antigens of 10 anti-PCNA-positive and 40 anti-PCNA-negative sera selected from 560 lupus patients were tested by immunoblotting, immunoprecipitation, and enzyme-linked immunosorbent assays (ELISAs). RESULTS: With one exception (serum OK), anti-PCNA-positive sera reacted exclusively with only the 34-kd polypeptide. In contrast, 14 of 40 anti-PCNA-negative sera reacted with multiple proteins within PCNA complexes. Most anti-PCNA-positive sera probably recognize as epitopes the binding sites for other proteins on PCNA, which are likely hidden when PCNA is complexed with other proteins. As a consequence, only serum OK reacted with the PCNA complex in a series of ELISAs. Using AK-PCNA as a competitive inhibitor, it was determined that serum OK reacts with both the 58-kd polypeptide and the 34-kd PCNA within complexes. Together with the results of a longitudinal analysis, these results suggest that the immune system of patient OK likely recognized the complexed PCNA protein, after which the autoimmune response spread to other elements of the complexes. CONCLUSION: Intermolecular-intrastructural help, leading to the spread of autoimmune response from PCNA to other proteins associated with its biologic function, plays a crucial role in the induction of the autoimmune response seen in lupus patients.

Antibodies, Monoclonal↗

PubMed1992

Proliferating cell nuclear antigen (PCNA/cyclin) in plant proliferating cells: immunohistochemical and quantitative analysis using autoantibody and murine monoclonal antibodies to PCNA.

Proliferating-cell nuclear antigen (PCNA), also known as cyclin, is synthesized in proliferative cells and recently was identified as DNA polymerase-delta auxiliary protein. In this paper, the association of PCNA to the proliferative cells of plants was analysed using both autoantibodies to PCNA obtained from a patient with systemic lupus erythematosus (SLE) and murine monoclonal antibodies. By immunohistochemical analysis, nuclei of cells around the growing point in soybean root tips reacted strongly with autoantibodies to PCNA in the serum from a patient with SLE. The plant PCNA in root tip cells was purified by ammonium sulfate fractionation, DEAE chromatography, and affinity chromatography. The partially purified plant PCNA was tested by immunoblotting and a 34 kD polypeptide reacted with both the human anti-PCNA autoantibody and a mouse monoclonal antibody against human PCNA (TOB 7). In addition, the purified plant PCNA reacted with both antibodies in enzyme-linked immunosorbent assay (ELISA). The binding of anti-PCNA serum to the animal PCNA was blocked by the plant PCNA in this ELISA. The association of PCNA with growing cells in plants was further confirmed by quantitative sandwich type ELISA using two murine monoclonal antibodies to PCNA, TOB7 and TO17. Those results suggested that PCNA in both plant and animal cells had the same immunological and biochemical characteristics and the plant PCNA might play an important role in cell growth, existing as it does in proliferating plant cells. The concentration of PCNA in soybean germ extract before germination was less than 5 ng ml-1 (protein concentration, 6.8 mg ml-1), but that of the root tip stem including the growing point increased to 887 ng ml-1 (protein concentration 3.8 mg ml-1) in the second day after germination.

Animals↗

PubMed1993

Immunostaining for proliferating cell nuclear antigen: its role in determination of proliferation in routinely processed human brain tumor specimens.

Alcohol- and formalin-fixed, paraffin-embedded samples of 71 brain tumors (35 gliomas, 22 metastatic carcinomas, 8 meningiomas and 6 other tumors) were investigated by immunocytochemistry with three different monoclonal antibodies against proliferating cell nuclear antigen (PCNA)/cyclin (19A2; 19F4; PC10). PC10 was found to work best; it is applicable to both alcohol- and formalin-fixed tumor samples. PCNA labeling indices (LIs) were compared in the same tumors with LIs obtained by Ki-67 immunostaining of frozen sections and by in vitro incubation with bromodeoxyuridine (BrdUrd); in the latter preparations, BrdUrd LIs could be compared with PCNA LIs in the very same areas of serial sections. In gliomas, PCNA LIs were 0.7-80.2% (mean 31.7%), in metastases 0-76.0% (mean 47.8%), and in meningiomas 0-53.0% (mean 19.3%). In general, PCNA LIs were highly significantly correlated with Ki-67 LIs (P = 0.0002) and BrdUrd LIs (P = 0.0001). However, when tumor subgroups are considered, only gliomas show a significant correlation with Ki-67 and BrdUrd LIs. Despite this statistical correlation, PCNA expression was out of proportion to proliferation indices as determined by both other methods in almost one third of all brain tumors. Immunocytochemistry for PCNA produces a broad spectrum of staining intensity of labeled nuclei, whose number is dependent upon the sensitivity of the immunocytochemical technique used. Thus, inter-observer and inter-laboratory variabilities in PCNA LI determination may occur. Overlapping of PCNA LIs between tumor subgroups of varying malignancy further limits the informational value for the individual case.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed2005

Anti-CD3 antibodies OKT3 and hOKT3gamma1(Ala-Ala) induce proliferation of T cells but impair expansion of alloreactive T cells; aspecifc T cell proliferation induced by anti-CD3 antibodies correlates with impaired expansion of alloreactive T cells.

OKT3, a mouse anti-human CD3 monoclonal antibody (mAb), has been used for decades to reverse acute transplant rejection. A humanized OKT3 with two alanine replacements on the CH2 domain, hOKT3gamma1(Ala-Ala), was generated to reduce side effects of OKT3. This study reports the effects of OKT3 and hOKT3gamma1(Ala-Ala) on responder T cells in mixed leukocyte cultures (MLC). T cells were purified from peripheral blood mononuclear cells (PBMC) and labeled with CFSE before culture with irradiated allogeneic PBMC in a MLC. Multiparameter flow cytometric analysis of MLC demonstrated logarithmic expansion of T cells with a memory phenotype. Treatment with either OKT3 or OKT3gamma1(Ala-Ala) prevented the logarithmic expansion of these cells. Instead, both OKT3 and hOKT3gamma1(Ala-Ala) induced nonspecific expansion of T cells with both naive and memory phenotype. The proliferating T cells in OKT3 or hOKT3gamma1(Ala-Ala) treated cultures expressed low levels of CD25, and showed a diminished Granzyme B expression compared to that of the untreated MLC, suggesting that these cells may not be fully functional. An array of cytokines in the MLC supernatant was analyzed, and IL-5 and IL-13 were significantly reduced by OKT3 or hOKT3gamma1(Ala-Ala) treatment. These results demonstrated that OKT3 and hOKT3gamma1(Ala-Ala) have similar effects on T cells in MLC. Both antibodies inhibited the logarithmic expansion of allo-reactive T cells, probably through inducing suboptimal proliferation of specific and non-specific T cells. This in vitro study provided one possible mechanism of the therapeutic effects of OKT3 and hOKT3gamma1(Ala-Ala) antibodies.

Antibodies, Monoclonal, Humanized↗

PubMed2002

Involvement of the peroxisome proliferator-activated receptor alpha in the immunomodulation caused by peroxisome proliferators in mice.

Peroxisome proliferators (PPs) are a large class of structurally diverse chemicals, which includes drugs designed to improve the metabolic abnormalities linking hypertriglyceridemia to diabetes, hyperglycemia, insulin-resistance and atherosclerosis. We have recently demonstrated that exposure of rodents to potent PPs indirectly causes a number of immunomodulating effects, resulting in severe adaptive immunosuppression. Since the peroxisome proliferator-activated receptor alpha (PPARalpha) plays a central role in mediating the pleiotropic responses exerted by PPs, we have compared here the immunomodulating effects of the PPs perfluorooctanoic acid (PFOA) and Wy-14,643 in wild-type and PPARalpha-null mice. The reductions in spleen weight and in the number of splenocytes caused by PP treatment in wild-type mice was not observed in PPARalpha-null mice. Furthermore, the reductions in thymus weight and in the number of thymocytes were potently attenuated in the latter animals. Similarly, the dramatic decreases in the size of the CD4(+)CD8(+) population of cells in the thymus and in the number of thymocytes in the S and G2/M phases of the cell cycle observed in wild-type mice administered PPs were much less extensive in PPARalpha-null mice. Finally, in contrast to the case of wild-type animals, the response of splenocytes isolated from the spleen of PP-treated PPARalpha-null mice to appropriate T- or B-cell activators in vitro was not reduced. Altogether, these data indicate that PPARalpha plays a major role in the immunomodulation caused by PPs. The possible relevance of these changes to the alterations in plasma lipids also caused by PPs is discussed.

Adjuvants, Immunologic↗

PubMed1993

Cell proliferation in prostatic adenocarcinoma: in vitro measurement by 5-bromodeoxyuridine incorporation and proliferating cell nuclear antigen expression.

We assessed cancer cell proliferation, a marker of the biologic activity of tumor cells, by evaluating bromodeoxyuridine (BrdUrd) incorporation and proliferating cell nuclear antigen (PCNA) expression. Prostatic carcinoma specimens (N = 48) were incubated in the presence of BrdUrd to label cells undergoing DNA synthesis, and immunocytochemical staining was performed with monoclonal antibodies to BrdUrd and PCNA and a standard indirect immunoperoxidase technique. The proportion of cells staining positively (labeling index or LI) for BrdUrd and PCNA was determined in 2 ways: by counting only high-power fields with the greatest concentration of stained cells (selected LI); or by counting cells in random fields (random LI). For BrdUrd the mean selected and random LIs were 3.08% and 1.62%, respectively; for PCNA they were 6.02% and 3.47%. Random and selected BrdUrd correlated well (r2 = 0.83), as did random and selected PCNA LIs (r2 = 0.86). However, a weaker correlation was noted when LIs of both techniques were compared, with the PCNA LI usually higher. The LIs of either technique correlated rather poorly with tumor grade and concentration of prostate-specific antigen, but correlated well with clinical stage as assessed by examination and imaging. In addition, either technique discriminated among tumors known to be pathologically confined (stages A and B) and those with extension to seminal vesicles (stage C) or metastatic to regional lymph nodes or bone (p < 0.019).

Adenocarcinoma↗

PubMed1997

Sulindac sulfide inhibits the proliferation of colon cancer cells: diminished expression of the proliferation markers PCNA and Ki-67.

We evaluated the effect of sulindac sulfide (SS), which reduces cell number and induces apoptosis in cultured colon cancer cells (CCCs), on expression of the proliferation markers PCNA and Ki-67 in HT-29 and HCT-15 CCCs; only the former express cyclooxygenases. DNA content and PCNA/Ki-67 expression were analyzed by bivariate flow cytometry. SS inhibited cell proliferation, determined by the reduced expression of PCNA and Ki-67, roughly by half at 72 h, and induced apoptosis (accounting for about two-thirds and one-third of the reduction in cell number, respectively). A similar effect of SS occurred in HT-29 and HCT-15 CCCs, and also in non-colonic cells, indicating that this rather general effect of SS on cultured cells is not dependent on inhibition of prostaglandin synthesis.

Adenocarcinoma↗

PubMed2000

Measuring cell proliferation in the rectal mucosa. comparing bromodeoxyuridine (BrdU) and proliferating cell nuclear antigen (PCNA) assays.

Cell proliferation in the human colorectum can be measured using bromodeoxyuridine (BrdU) or proliferating cell nuclear antigen (PCNA) assays. Using data from the National Cancer Institute's Polyp Prevention Trial, these two assays are compared using correlation coefficients and variance components analysis. Adjusting for fixed as well as for the random effects of between-biopsy and scoring variation, the estimated correlation is 0.46 for the log labeling index and 0.45 for log proliferative height. This is an estimate of the highest correlation that can be achieved by taking multiple biopsies scored by multiple scorers. For single biopsies, the estimated correlation is 0.16 and 0.10, respectively. There are significant differences between the variance components for the two assays. For example, for log labeling index, PCNA has a lower variation between biopsies than BrdU, but higher variation between scorings. When used in a clinical or epidemiological setting, it is important to take multiple biopsies at multiple time points.

Adenoma↗

PubMed2003

Validation of the use of proliferation markers in canine neoplastic and non-neoplastic tissues: comparison of KI-67 and proliferating cell nuclear antigen (PCNA) expression versus in vivo bromodeoxyuridine labelling by immunohistochemistry.

In order to evaluate the suitability of Ki-67 and proliferating cell nuclear antigen (PCNA) for determination of proliferative activity, the immunohistochemically determined nuclear expression of these antigens in canine non-neoplastic and neoplastic tissues was compared with the results of in vivo bromodeoxyuridine (BrdU) labelling, which - by measurement of the fraction of S-phase cells - is considered as the standard in the analysis of proliferative activity. The samples investigated consisted of non-neoplastic mammary and lymphoid tissues, and of benign and malignant (primary/metastatic) mammary tumours, and malignant lymphomas. Great regional heterogeneity prevented determination of an overall labelling index (LI) in normal lymphoid tissues. In the remaining combined group of samples, LI values were significantly ranked in the order PCNA>Ki-67>BrdU. However, the correlation of Ki-67 or PCNA as compared to BrdU LI values was only moderate in the combined group [approximately 0.5, Spearman rank test] as well as in most subgroups, whilst it was very poor in the group of primary mammary cancers. These observations indicate that Ki-67 or PCNA LIs as markers of proliferation do not evenly match in vivo BrdU labelling.

Animals↗

PubMed1994

Inhibition of gastric cancer cell proliferation by antisense oligonucleotides targeting the messenger RNA encoding proliferating cell nuclear antigen.

Proliferating cell nuclear antigen (PCNA) is a nuclear protein that regulates DNA synthesis by DNA polymerase delta, and is essential for DNA replication. PCNA expression level is related to the malignancy of gastric cancer cells. Seven different gastric cancer cell lines and two kinds of control cell lines were treated with antisense oligonucleotides complementary to the messenger RNA of PCNA. Treatment of each gastric cancer cell line with antisense oligonucleotides at concentration of 10-40 microM inhibited the cell growth, colony formation and PCNA protein production in a dose-dependent manner, but only affected normal cells slightly. A random sequence oligomer showed no effect. These results show that PCNA is essential for gastric cancer cell proliferation and that the use of synthetic oligonucleotides is an effective way of producing antisense-mediated changes in the behaviour of human gastric cancers.

Base Sequence↗

PubMed1989

A method for measuring lymphocyte proliferation in mixed lymphocyte cultures using a nuclear proliferation antigen, Ki-67, and flow cytometry.

The mixed lymphocyte culture procedure using tritiated thymidine (3H-TdR) incorporation is time consuming and labor intensive, therefore costly. With the use of a fluorescent antibody to a human nuclear proliferation antigen, Ki-67, and flow cytometry, mixed lymphocyte cultures on 20 families of renal and bone marrow transplant patients and normal controls were performed. In this method for measuring lymphocytic proliferation, previously developed by the authors, the entire culture and staining procedures are performed in microculture plates. Finally, the cell suspensions are aspirated with a microsampler to be analyzed by a flow cytometer. Excellent correlation of the percentage of Ki-67-positive cells and the counts per minute (CPM) of 3H-TdR incorporated into the DNA was obtained. This method eliminates the use of radioactive labels, is less time consuming, and yields results two to three days earlier than the radioactive method. In addition, the authors dual-labeled the lymphocyte nuclei with Ki-67 and propidium iodide (Ki-67/PI). This permitted the comparison of the appearance of nuclear antigen with the various phases of the cell cycle.

Bone Marrow Transplantation↗

PubMed2004

Fibrates induce hepatic peroxisome and mitochondrial proliferation without overt evidence of cellular proliferation and oxidative stress in cynomolgus monkeys.

There is little primate risk factor data in the literature evaluating the relationship between proposed mechanisms of PPAR agonist-induced hepatocarcinogenesis at clinically relevant therapeutic exposures. These studies were conducted to characterize the hepatic effects of fenofibrate and ciprofibrate in the cynomolgus monkey. Male cynomolgus monkeys were given fenofibrate (250, 1250 or 2500 mg/kg/day) or ciprofibrate (3, 30, 150 or 400 mg/kg/day) for up to 15 days. The highest doses used were approximately 4 times (fenofibrate) and 9.4 times (ciprofibrate) the human therapeutic exposure for these agents based on AUC (area under the curve). For both compounds, there was a treatment-related increase in liver weight and periportal hepatocellular hypertrophy, which was related to increases in peroxisomes (up to 2.8 times controls) and mitochondria (up to 2.5 times controls). An increase in smooth endoplasmic reticulum probably contributed to the hypertrophy. There was no indication of cell proliferation as determined by the number of mitotic figures and this was confirmed by evaluating cell proliferation by immunohistochemical staining for the Ki-67 antigen. Consistent with the findings by light microscopy, there was no treatment-related effect on the level of mRNA for proteins known to be involved in the control of hepatocyte cell division or apoptosis (e.g. P21, Cyclin D1, PCNA, CDKN1A). Furthermore, there was minimal indication of oxidative stress. Thus, there was no evidence of lipofuscin accumulation, and there was no remarkable increase in the mRNA levels for most proteins known to respond to oxidative stress (e.g. catalase, glutathione peroxidase). A mild induction in the mRNA levels of cellular beta-oxidation and detoxification enzymes (e.g. acyl CoA oxidase, thioredoxin reductase) was observed. Collectively, the data from these studies suggest that the primate responds to PPARalpha agonists in a manner that is different from the rodent suggesting that the primate may be refractory to PPAR-induced hepatocarcinogenesis.

Acyl-CoA Oxidase↗

PubMed1997

The role of proliferating cell nuclear antigen (PCNA) in differentiating idiopathic orbital inflammatory disease and lymphoid proliferations.

The purpose of the present study was to determine whether proliferating cell nuclear antigen (PCNA), an immunohistochemical marker for a nuclear protein abundant in actively proliferating (dividing) cells, is useful as an aid in differentiating idiopathic orbital inflammatory syndrome (IOIS) from lymphoproliferative lesions (LLs). Records of all patients with IOIS and LLs were studied retrospectively. Tissue biopsy specimens from four patients with IOIS and nine patients with LLs were examined. The diagnosis in each case was based on presenting signs and symptoms, orbital computed tomography (CT) and/or magnetic resonance (MR) scans, histopathologic criteria, and follow-up data consistent with the entity. These findings were correlated with the percentage of B- and T-cells in the lesions as well as with the number of cells that demonstrated staining for PCNA in formalin-fixed tissue. PCNA activity was markedly increased in the higher grade (HG) lymphoma group as compared to that in the low grade (LG) lymphoma and idiopathic inflammatory group. Lymphoma cases showed a significantly increased B-/T-cell ratio compared to IOIS lesions. PCNA activity in conjunction with the ratio of B-/T-cells may be a helpful immunohistologic adjunct for differentiating purely inflammatory lesions of the orbit from lymphoid tumors. Further studies are necessary to compare PCNA activity in fresh frozen tissue with that in formalin-fixed tissue.

B-Lymphocytes↗